`BookProof.DirectSumEdge.quadForm_dsOp_eq_sum` (H : ∀ i, D i →ₗ[ℂ] G i) (x : dsCore D) : quadForm (dsOp H) x = ∑ i ∈ supportFinset x, quadForm (H i) ⟨((x : lp G 2) : ∀ i, G i) i, x

Proved

BookProof.DirectSumEdge.quadForm_dsOp_eq_sum

by leonardopedro · Oct 7, 2026 · Mathlib 0df444a (Lean v4.33.1)

theoremstimepiece

Prove the following Lean 4 theorem from ChapterDirectSumEdge.

BookProof.DirectSumEdge.quadForm_dsOp_eq_sum (H : ∀ i, D i →ₗ[ℂ] G i) (x : dsCore D) : quadForm (dsOp H) x = ∑ i ∈ supportFinset x, quadForm (H i) ⟨((x : lp G 2) : ∀ i, G i) i, x.2.2 i⟩

Formalization note: Lean 4 identifier BookProof.DirectSumEdge.quadForm_dsOp_eq_sum.

Preamble

-- Generated from ChapterDirectSumEdge.lean — theorem BookProof.DirectSumEdge.quadForm_dsOp_eq_sum
import Definitions.Def_ChapterFarisLavine
import Mathlib
import Definitions.Def_ChapterDirectSumEdge
import Definitions.Def_ChapterDirectSumEsa
import Definitions.Def_ChapterFarisLavineCore
open BookProof.DirectSumEsa
open BookProof.DirectSumEdge



open BookProof.FarisLavine BookProof.DirectSumEsa

noncomputable section

variable {ι : Type*} {G : ι → Type*} [∀ i, NormedAddCommGroup (G i)]
  [∀ i, InnerProductSpace ℂ (G i)] {D : ∀ i, Submodule ℂ (G i)}

Formal statement

theorem BookProof.DirectSumEdge.quadForm_dsOp_eq_sum (H : ∀ i, D i →ₗ[ℂ] G i) (x : dsCore D) :
    quadForm (dsOp H) x
      = ∑ i ∈ supportFinset x,
          quadForm (H i) ⟨((x : lp G 2) : ∀ i, G i) i, x.2.2 i⟩ := by sorry

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